Switzerland’s livestock production causes high environmental costs and depends strongly on feed imports. While plant-based protein demand increases, the local grain legume production is negligible ( ~ 9000 hectares). Here, we investigated the potential of sustainable legume protein production based on an expert survey followed by a quantitative analysis based on yield, soil, terrain and climate data. Pea, soybean and faba bean showed high potential for Swiss agriculture given adaptions in policy, pricing and breeding. The potential grain legume production area was 107,734 hectares on suitable arable land (Scenario I). Switzerland’s self-sufficiency could be increased by cutting imports and maximizing legume production on 181,479 hectares (Scenario II) in expense of grassland and fodder maize. This would replace approximately 41% of animal protein consumption with plant-based protein, preserving 32% of milk and 24% of meat protein. In conclusion, domestic legume production could be substantially increased while improving human and environmental health.

Lupins are an interesting arable crop for cultivation. They provide a source of vegetable protein, can bind nitrogen in the soil as a legume, and have commercialisation potential thanks to their wide range of uses. However, lupins contain alkaloids, plant defence substances that can be toxic to humans and animals above a certain dose. The alkaloid content can vary depending on the variety and growing conditions, and should be determined after harvesting. The fact sheet provides information and guidance on analysing and reducing alkaloids in lupins and is intended for producers, collection centres, processing companies and all interested parties in the field. Some sections of this fact sheet refer specifically to the Swiss context, for example, the Swiss food law.

Narrow-leafed lupins (Lupinus angustifolius L.) were fully domesticated as a valuable grain legume crop in Australia during the mid-twentieth century. Pedigree records are available for 31 released varieties and 93 common ancestors from 1967 to 2016, which provides a rare opportunity to study genetic diversity and population inbreeding in a crop following a domestication bottleneck. From the 1930s to 1960s, partially domesticated germplasm was exchanged among lupin breeders in eastern and western Europe, Australia and USA. Mutants of two founder parents contributed to the first fully domesticated narrow-leafed lupin variety ‘Uniwhite’ in 1967. Four Phases of breeding are proposed after domestica-tion in the Australian lupin breeding program: Foundation (1967 – 1987), First Diversification (1987 – 1998), Exploitation (1998 – 2007), and Second Diversifi-cation (2007 – 2016) Phases. Foundation Phase varieties had only two or three founder parents following the domestication bottleneck and high average coeffi-cient of coancestry (f = 0.45). The First Diversification Phase varieties were de-rived from crosses with wild lupin ecotypes, and varieties in this Phase had lower average coefficient of coancestry (f = 0.27). Population coancestry increased in varieties of the Exploitation Phase (f = 0.39). The rate of inbreeding (ΔF) between the First Diversification and Exploitation Phase (10 years) was 0.09 per cycle, which equates to 9% loss of alleles per cycle due to random drift and low effec-tive population size (Ne = 5.4), assuming two 5-year cycles. New genetic diversity was introduced in the Second Diversification Phase varieties (f = 0.24) following more crossing with wild lupins. Genetic progress in Australian lupin breeding so far has been substantial with improvements in grain yield and disease resistance, but narrow genetic diversity will limit future genetic progress. The pedigree of the latest varieties includes 39.1% from three founder varieties in the domestication bottle-neck and 48.3% from 9 wild ecotypes that survived 50 years of selection. In terms of conservation genetics, the Australian lupin breeding program is a critical-ly endangered population, and subject to excessive random drift. Migration of genetic diversity from wild lupins or exchange with international breeding pro-grams will improve long-term genetic gain and effectiveness of genomic selection.